Analog data-input device provided with a pressure sensor of a microelectromechanical type

• US 20060262088A1
• Filed: 03/30/2006
• Published: 11/23/2006
• Est. Priority Date: 03/31/2005
• Status: Active Grant

• Current Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Inventors: Combi, Chantal, Baldo, Lorenzo, Del Sarto, Marco, Sassolini, Simone
• Granted Patent: US 8,044,929 B2
• Time in Patent Office: Days
• US Class Current: 345/156
• CPC Class Codes: G01L 19/141 Monolithic housings, e.g. molded or one-piece housings
• CPC Class Codes: G01L 19/147 Details about the mounting of the sensor to support or covering means
• CPC Class Codes: G01L 9/0045 Diaphragm associated with a buried cavity
• CPC Class Codes: G01L 9/0054 integral with a semiconducting diaphragm
• CPC Class Codes: G06F 3/0338 with detection of limited linear or angular displacement of an operating part of the device from a neutral position, e.g. isotonic or isometric joysticks
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: H01H 13/785 characterised by the material of the contacts, e.g. conductive polymers
• CPC Class Codes: H01H 2201/02 Piezo element
• CPC Class Codes: H01H 2201/036 Variable resistance
• CPC Class Codes: H01H 2221/012 Joy stick type
• CPC Class Codes: H01H 2239/01 combined with other elements on the same substrate
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/16195 Flat cap [not enclosing an internal cavity]
• CPC Class Codes: H01L 2924/181 Encapsulation

Abstract

In a data-input device an actuator element that can be manually actuated, and a sensor mechanically coupled to the actuator element. The sensor is formed in a body of semiconductor material housing a first sensitive element, which detects the actuation of the actuator element and generates electrical control signals. The first sensitive element is a microelectromechanical pressure sensor, formed by: a cavity made within the body; a diaphragm made in a surface portion of the body and suspended above the cavity; and piezoresistive transducer elements integrated in peripheral surface portions of the diaphragm in order to detect its deformations upon actuation of the actuator element.

Claims

1. A data-input device, comprising:

an actuator element;

a sensor mechanically coupled to said actuator element and including a body made of semiconductor material, said body housing first and second sensitive elements configured to detect respective directions of actuation of the actuator element and to generate respective electrical control signals, each of said first and second sensitive elements including a microelectromechanical pressure sensor.

2. The device according to claim 1 wherein each of said first and second sensitive elements comprises a cavity formed in said body, a diaphragm formed in a surface portion of said body and suspended above said cavity, and piezoresistive transducer elements, which are integrated in peripheral surface portions of said diaphragm and detect deformations of said diaphragm upon actuation of said actuator element.

3. The device according to claim 1 wherein said sensor further comprises:

a package (35) having a chamber (36) housing said body (10);

an elastomeric material (37), filling at least partially said chamber (36); and

a flexible membrane (39), closing said chamber (36) at the top and delimiting a main surface of said package (35).

4. The device according to claim 3 wherein said flexible membrane forms said actuator element.

5. The device according to claim 3 wherein said actuator element comprises a flexible structure shaped to form keys, having a control portion arranged on top of said flexible membrane.

6. The device according to claim 1 wherein said body houses further sensitive elements, each of said further sensitive elements configured to detect a respective direction of actuation of said actuator element.

7. The device according to claim 6, wherein said body further houses an interface electronic circuit, electrically connected to said sensitive elements.

8. The device according to claim 6 wherein said first and second sensitive elements and further sensitive elements are arranged with respect to one another in a geometrical configuration chosen from among a triangle, a cross, and an array.

9. A data-input device, comprising:

an actuator element; and

a sensor mechanically coupled to said actuator element and including first and second sensitive elements integrated in respective bodies of semiconductor material, each of said first and second sensitive elements including a microelectromechanical pressure sensor configured to detect a respective direction of actuation of said actuator element and to generate electrical control signals.

10. The device according to claim 9 wherein said sensor also includes further sensitive elements integrated in respective bodies of semiconductor material, each of said further sensitive elements including a microelectromechanical pressure sensor configured to detect a respective direction of actuation of said actuator element, and wherein said first and second sensitive elements and further sensitive elements are arranged with respect to one another in a geometrical configuration chosen from among a triangle, a cross, and an array.

11. An electronic apparatus comprising:

a data-input device having

an actuator element;

a sensor mechanically coupled to said actuator element and including a body made of semiconductor material, said body housing first and second sensitive elements configured to detect respective directions of actuation of the actuator element and to generate respective electrical control signals, each of said first and second sensitive elements including a microelectromechanical pressure sensor.

12. The apparatus according to claim 11, comprising a display controllable by means of said data-input device.

13. The apparatus according to claim 11 wherein the apparatus is one of:

a mobile phone, a PDA, a personal computer, a game-computer console, or a remote control.

14. A pressure sensor comprising:

a body of semiconductor material;

a plurality of diaphragms formed over respective cavities in the body;

a circuit formed in the body and configured to detect deflection of each of the plurality of diaphragms and produce a signal corresponding to a degree of deflection of each; and

a package within which the body is mounted such that pressure on a region of an upper surface of the package results in selective deflection of one or more of the plurality of diaphragms that lie closest to the region of the upper surface.

15. The pressure sensor of claim 14, comprising a plurality of piezoresistive elements formed in the body adjacent to each of the plurality of diaphragms and configured to be responsive to deflection of the respective diaphragm, the circuit being coupled to the piezoresistive elements such that responses of the piezoresistive elements to deflection of the respective diaphragm are detected by the circuit.

16. The pressure sensor of claim 14 wherein the upper surface of the package includes a flexible membrane, and wherein a space between the flexile membrane and the diaphragm is filled with an elastomeric material cofigurd to transmit pressure to the diaphragm.

17. The pressure sensor of claim 14 wherein the plurality of diaphragms are arranged with respect to one another in a geometrical configuration chosen from among a triangle, a cross, and an array.

18. A device comprising:

a pressure sensor including a body of semiconductor material and a plurality of diaphragms formed over respective cavities in the body;

deflection means for selectably deflecting individual ones of the plurality of diaphragms; and

a circuit configured to detect deflection of each of the plurality of diaphragms and command operation of one of a plurality of functions of the device in response to a combination of deflections detected.

19. device of claim 18 wherein the circuit is further configured to detect a degree of deflection of each of the plurality of diaphragms.

20. The device of claim 18 wherein the deflection means comprises a keypad.

21. the device of claim 18 wherein the deflection means comprises a membrane positioned above the body of semiconductor material, and a space between th4e membrane and the body filled with an elastomeric material.